This invention relates to a method of drying a tool and, more particularly, to a method of drying an injection molding tool by circulating dry air from a drying device through a chamber containing the tool and returning moist air to the drying device.
When producing plastic parts in the injection molding process, it is necessary to cool the injection molding tool in order to reduce the station times. The more effective the cooling, that is, the faster the heat can be withdrawn from the produced part, the more rapidly the plastic part will solidify and can be removed from the tool.
It is known to be advantageous to supply coolant to the tool at a temperature of approximately 5.degree. C. If the finished injection molded plastic part is moved in the case of a tool cooled in this manner, condensation water is formed very rapidly on the cooled tool because of the ambient air. During the next injection molding operation, this condensation water will cause a surface waviness on the surface of the plastic part to be produced. Attempts have been made to remove moisture from the tool by means of drying air. This drying air was blown directly onto the tool and flowed out into the atmosphere. In order to prevent an undefined outflow, the tool was partially enclosed.
A disadvantage of the previously described method is that a very large amount of air is required in order to keep the tool sufficiently dry. The large amount of supplied drying air naturally also results in a high energy requirement so that the efficiency of such a drying device was extremely unfavorable. The previously described method also allowed harmful vapors to escape into the atmosphere.